Conformal coating of parylene for surface anti-adhesion in polydimethylsiloxane (PDMS) double casting technique

As a simple method to fabricate a high quality copy of master, PDMS double casting technique has been more and more popular in microfluidics chips and bioMEMS application. In this work, the method in which conformal coating of parylene C serves as a demolding anti-adhesion layer in PDMS double casting technique was proposed. First casting was carried out onto master mold to generate negative PDMS mold and second casting was done onto negative PDMS mold likewise to generate positive PDMS replica with the same structure as master mold. Microstructures with aspect ratio from 4:1 to 20:1 and sharp angle from 5° to 40° were successfully obtained by using this new method. Experiments show replicas remain high fidelity to their masters. This new method of surface anti-adhesive treatment is environment friendly. Moreover, a single coating of parylene C can make the treated mold keep its anti-adhesive property for long lifecycle regardless of the number of replica molding cycles.

► We propose parylene C coating serves as surface anti-adhesion layer in PDMS double casting technique.
► Microstructure copies with different aspect ratios and sharp angles can be fabricated from master by using this new method.
► This new method is environment friendly.
► A single coating of parylene C can keep anti-adhesive property on its substrate for long lifetime regardless of the number of replica molding cycles.